Review construction of orthogonal carriers

1 files changed, 49 insertions, 0 deletions

diff --git a/doc/thesis/figures/tikz/qam-example.tex b/doc/thesis/figures/tikz/qam-example.tex
new file mode 100644
index 0000000..2d37f55
--- /dev/null
+++ b/doc/thesis/figures/tikz/qam-example.tex
@@ -0,0 +1,49 @@
+% vim: set ts=2 sw=2 noet:
+
+%% TODO: finish this figure
+
+\begin{tikzpicture}
+	% Draw digital signals
+	\begin{scope}[font = \ttfamily\footnotesize, text = blue!70!white]
+		\node[above = 1mm of M, xshift = 2mm] {\(\ldots 1100101\)};
+		\node[above = 7mm of vmi, xshift = 3mm]
+			{\(\overbracket[.8pt]{\,11\ldots 00\,}^{\sqrt{M} \text{ bits}}\)};
+	\end{scope}
+
+	% Draw analog waveform
+	\begin{scope}[font = \ttfamily\tiny]
+		\coordinate (O) at ($(mi)+(-2mm,10.5mm)$);
+
+		\node[left, red!70!white, anchor = east, text width = 8mm, align = right]
+			at ($(O) + (-2mm,0)$) {\(2^{\sqrt{M}}\) levels};
+
+		\foreach \y in {-3mm,0,3mm} {
+			\draw[gray, densely dotted] (O) ++(-2mm,\y) -- ++(22mm,0);
+		}
+
+		\draw[thick, draw = red!70!white] (O)
+			-- ++(3mm,0) -- ++(0,-3mm) -- ++(3mm,0) -- ++(0,6mm)
+			-- ++(3mm,0) -- ++(0,-3mm) -- ++(3mm,0) -- ++(0,-3mm)
+			-- ++(3mm,0) -- ++(0,3mm)  -- ++(3mm,0);
+	\end{scope}
+
+	% Draw constellation diagram
+	\begin{scope}
+		\coordinate (O) at ($(S)+(-7mm,8mm)$);
+		\draw[gray, -latex] (O) ++(-2mm,0) -- ++(12mm,0) node[right] {\tiny \(\phi_i\)};
+		\draw[gray, -latex] (O) ++(0,-2mm) -- ++(0,12mm) node[above] {\tiny \(\phi_q\)};
+
+		\node[
+			circle, thick,
+			minimum size = 3pt,
+			inner sep = 0, outer sep = .8pt,
+			draw = gray, fill = red!50!white
+		] (P) at ($(O)+(5mm, 4mm)$) {};
+
+		\node[gray, above right] at (P) {\tiny \(s\)};
+
+		\draw[gray, densely dotted]
+			(P) -- (P |- O)
+			(P) -- (P -| O);
+	\end{scope}
+\end{tikzpicture}